Resealable beverage can end and methods relating to same

ABSTRACT

A resealable and recloseable beverage can end closure includes a base plate beneath the center panel and a tab plate above the center panel. The closure is slidable relative to the center a panel to uncover the pour aperture and then to position the closure over the pour aperture to enable resealing.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 13/685,085 filed Nov. 26, 2012, which is a continuation of U.S. application Ser. No. 12/267,159 filed Nov. 7, 2008, which claims priority to Great Britain Application Number 0807762.0 filed Apr. 29, 2008, Great Britain Application Number 0815360.3 filed Aug. 22, 2008, and U.S. Provisional Application No. 60/986955, filed Nov. 9, 2007, each of which is incorporated herein by reference in its entirety. This application is also continuation of U.S. patent application Ser. No. 13/202,224 filed Nov. 4, 2011, which claims priority to PCT Application No. PCT/EP10/52159 filed Feb. 19, 2010, each of which is incorporated herein by reference in its entirety.

FIELD OF TECHNOLOGY

The present invention relates to packaging for beverages and, more particularly, to a resealable beverage can end, a resealable closure, and methods relating to same.

BACKGROUND

The structure and functionality of commercial beverage cans have been optimized over the years. Yet commercial beverage cans have the drawback of being unable to reclose after initial opening. Reclosing beverage cans is made more difficult by the dissolved carbon dioxide or other gases in a carbonated beverage that leaves the solution and tends to increase the pressure in the headspace. Several resealable can end designs have been proposed by the prior art, but none have reached commercial acceptance.

Consumers of beverages in plastic bottles, on the other hand, often reseal the bottle by screwing its threaded closure onto the bottle finish. This attribute appeals to consumers.

Accordingly, there is a need for a resealable beverage can that is easy or intuitive to use, has a viable cost, and is not overly complex.

Furthermore, conventional beverage cans are designed to vent the excess pressure in the can upon initial opening. Ends used for such beverage cans have a score line defining an aperture from which the contents of the can may be dispensed and a smaller score line defining a vent. As the tab is lifted, first the vent score severs, allowing release of the gases that have built up in the headspace of the beverage can, and then the aperture score ruptures, to define an aperture through which the contents of the beverage can may be dispensed. Thus, a user simply lifts the tab to effect both venting and thereafter opening of the beverage can.

The opening device described in WO 2007/128810 assigned to Crown Packaging Technology, Inc. describes an embodiment in which the tab includes a pin, which engages in a vent hole in the end panel. A disadvantage of this arrangement is that upon re-closing of the device, a user must manually reinsert the pin into the vent hole to reseal the can end to prevent leaks and maintain carbonation (if any) of the product inside the container to which the opening device is applied.

SUMMARY

In one embodiment, a metal can end for a beverage can body includes a center panel surrounded by a seaming portion. The center panel is adapted to be joined to the periphery of the beverage can body by a double-seam. The center panel defines an aperture through which the contents of the beverage can body may be dispensed. A peripheral edge of the aperture is finished by a curl and the aperture is adapted to receive a separate closure. The separate closure is capable of sliding relative to the center panel between a closed position, in which the aperture and the closure together form a seal, and an open position, in which the aperture is exposed.

In another embodiment, a metal can end for a beverage can body includes a peripheral wall, a countersink, and a center panel. The center panel defines an aperture through which the contents of the beverage can body may be dispensed. The center panel includes a curl disposed about the aperture. The center panel is adapted to receive a separate closure. The separate closure is configured to slide along the center panel between: i) a sealed position, in which the closure contacts the center panel about the aperture to form a seal, ii) an intermediate position, in which the closure is proximate the aperture but not sealed, and (iii) a fully open position, in which the aperture is exposed to enable pouring the contents of the beverage can body through the aperture.

In another aspect, the disclosure recites a method of manufacturing a metal can end for a beverage can body. The method includes pressing a metal can end from sheet metal. The metal can end has a center panel surrounded by a seaming portion. The seaming portion is adapted to be joined to a periphery of the beverage can body by a double-seam. The method includes cutting an aperture through the center panel of the metal can end. The method also includes forming a depression around the aperture, at least part of which is formed to create a preliminary curl around the aperture. The method also includes coining the preliminary curl to form a curl around the aperture.

BRIEF DESCRIPTION OF THE FIGURES

The present technology provides a recloseable end for a beverage can and related methods for making and using the recloseable end. The technology will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1A is a perspective view of a combination can end and a resealable closure illustrating a first embodiment in the fully closed position;

FIG. 1B is a perspective view of the first embodiment in an intermediate position;

FIG. 1C is a perspective view of the first embodiment in the fully open position;

FIG. 2A is a cross sectional view of the first embodiment in its fully closed position;

FIG. 2B is an enlarged view of a portion of FIG. 2A depicting a sealing portion of the end;

FIG. 2C is a cross sectional view of an alternative embodiment of the can end in its fully closed position viewed orthogonal to the tab;

FIG. 2D is a cross sectional view of the first embodiment of the can end in its intermediate position;

FIG. 2E is a cross sectional view of the first embodiment in its fully open position;

FIG. 3A is a top perspective view of the top plate of the closure of the first embodiment in its pre-assembled state;

FIG. 3B is a bottom perspective view of the top plate of the first embodiment in its pre-assembled state;

FIG. 4A is a top perspective view of the top plate showing an alternative tab configuration;

FIG. 4B is a bottom perspective view of the top plate showing an alternative tab configuration;

FIG. 5A is a top perspective view of an alternative configuration of the top plate of the closure of the first embodiment in its pre-assembled state;

FIG. 5B is a bottom perspective view of the top plate shown in FIG. 5A;

FIG. 6 is a perspective view of a base plate of the first embodiment in its pre-assembled state;

FIG. 7 is a perspective view of an alternative configuration of the base plate corresponding to the top plate illustrated in FIGS. 5A and 5B;

FIG. 8A is a perspective view of a base plate having vent slots;

FIG. 8B is a perspective view of an alternative top late arrangement suitable for use with the base plate shown in FIG. 8A having vent slots which allow air between the top plate and the base plate;

FIG. 8C is an isometric view of the closures shown in FIGS. 8A and 8B when assembled onto a can end/body, illustrating vent arches in the assembled closure to enable air to enter the closure, when the top plate and base plate are arranged in a venting position;

FIG. 9A is a cross sectional view of a an alternative closure assembled onto a can end/body in an unopened position;

FIG. 9B is a cross sectional view of the closure shown in FIG. 9A upon reclosing the can with the tab lifted to reengage the bore seal and face seal;

FIG. 10A is a top view of a first alternative top plate configuration, in a closed position, that may be employed with first embodiment closure;

FIG. 10B is a perspective view of the top plate configuration shown in FIG. 10A showing the closure in an intermediate position;

FIG. 11A is a top view of a second alternative top plate configuration, in a closed position that may be employed with first embodiment closure;

FIG. 11B is a perspective view of the top plate configuration shown in FIG. 11A showing the closure in an intermediate position;

FIG. 12A is a top view of a third alternative top plate configuration, in a closed position that may be employed with first embodiment closure;

FIG. 12B is a perspective view of the top plate configuration shown in FIG. 12A showing the closure in an intermediate, venting position;

FIG. 13A is a perspective view of the top plate configuration shown in FIG. 10A having an alternative structure for tamper evidence (TE) in a closed position;

FIG. 13B is a perspective view of the top plate configuration shown in FIG. 13A in which the alternative TE structure has been activated;

FIG. 13C is a cross sectional view of the top plate configuration shown in FIG. 13A having an alternative structure for tamper evidence (TE) in a closed position;

FIG. 13D is a cross sectional view of the top plate configuration shown in FIG. 13A in which the alternative TE structure has been activated;

FIG. 14A is a perspective cross sectional view of an alternative closure assembled onto a can end/body in its fully closed position and having a vent plug biased towards its sealed position by a spring;

FIG. 14B is a perspective cross sectional view of the closure shown in FIG. 14A with the spring and vent plug removed, for clarity;

FIG. 15 is a perspective view depicting the closure shown in FIG. 14A affixed to a can body;

FIG. 16 is a bottom view of the closure shown in FIG. 14A with the base plate removed for clarity;

FIG. 17A is a perspective cross sectional view of a resealable can end with the closure shown in FIG. 14A in its intermediate, vented position;

FIG. 17B is a perspective cross sectional view of a resealable can end with the closure shown in FIG. 14A in another intermediate position in which the seals are disengaged;

FIG. 17C is a perspective cross sectional view of a resealable can end with the closure shown in FIG. 14A in its fully open position and the aperture exposed;

FIG. 18A is a top perspective view of the top plate of the closure shown in FIG. 14A;

FIG. 18B is a bottom perspective view of the top plate of the closure shown in FIG. 14A;

FIG. 19A is a top perspective view of the base plate of the closure shown in FIG. 14A;

FIG. 19B is a bottom perspective view of the base plate of the closure shown in FIG. 14A;

FIG. 20A is a perspective cross sectional view of another embodiment of a resealable can end having a closure in its fully closed position and having a vent plug biased towards its sealed position by a spring;

FIG. 20B is a perspective cross sectional view of the resealable can end shown in FIG. 20A with the closure in s intermediate, vented position;

FIG. 21A is a perspective view of a spring plate in its “as molded”, unstressed state;

FIG. 21B is a perspective view of the spring plate shown in FIG. 21A in its “actuated”, loaded state;

FIG. 22 is a perspective cross sectional view of another embodiment closure in its fully closed position;

FIG. 23 is a cross sectional view of the closure shown in FIG. 22;

FIG. 24 is a top perspective view of the closure shown in FIG. 22;

FIG. 25 is a bottom perspective view of the closure shown in FIG. 22.

FIG. 26A is a plan view of a can end according to the invention;

FIG. 268 is a cross section view of the can end shown in FIG., 26A taken along the line A-A;

FIG. 26C is a detailed portion of the cross section view of FIG. 26B, indicated by circle B, showing a curl around the perimeter of the aperture in the can end;

FIG. 26D is a portion of the cross section view of FIG. 26B, indicated by circle C, indicating the distances between various features of the can end. A step wise progression, method and tooling used to form the final can end is also described, by way of example only, with reference to the attached drawings, in which:

FIG. 27A is a perspective view of a can end;

FIG. 27B is a plan view of the can end blank illustrated in FIG. 27A;

FIG. 27C is a side cross section view of the can end blank illustrated in FIG. 27B taken along the line A-A;

FIG. 28A is a perspective view of the can end blank having a hole punched through the planar center panel thereof;

FIG. 28B is a plan view of the can end blank illustrated in FIG. 28A;

FIG. 28C is a side cross section view of the can end blank illustrated in FIGS. 28A and 28B, with an inset detailed view of the portion indicated by the letter B;

FIG. 29A illustrates tooling suitable for forming a depression around the periphery of the hole in the can end blank, in a start position, in which the can end blank is clamped in position and no depression has been formed yet, with an inset detailed view of the portion indicated by the letter D;

FIG. 29B illustrates the same tooling as illustrated in FIG. 29A, in a finish position, in which an annular punch has formed a depression around the periphery of the hole in the can end blank;

FIG. 30A is an perspective view of the can end blank having a hole punched through the planar center panel thereof and a depression formed around the periphery of the hole;

FIG. 30B is a plan view of the can end blank illustrated in FIG. 30A;

FIG. 30C is a side cross section view of the can end blank illustrated in FIGS. 30A and 30B, with an inset detailed view of the portion indicated by the letter B;

FIG. 31A illustrates tooling suitable for drawing the raw edge of the hole into the start of a curl, in a start position, in which the can end blank is clamped in position and no drawing has yet taken place, with an inset detailed view of the portion indicated by the letter E;

FIG. 31B illustrates the same tooling as illustrated in FIG. 31A, in a finish position, in which a draw punch has been moved through the hole thereby forming the start of a curl, with an inset detailed view of the portion indicated by the letter E;

FIG. 32A is a perspective view of the can end blank having a hole punched through the planar center panel thereof and the start of a curl formed around the periphery of the hole;

FIG. 32B is a plan view of the can end blank illustrated in FIG. 32A;

FIG. 32C is a side cross section view of the can end blank illustrated in FIGS. 32A and 32B, with an inset detailed view of the portion indicated by the letter B;

FIG. 33A is a perspective view of the finished can end having a hole punched through the planar center panel thereof and a curl formed around the periphery of the hole;

FIG. 33B is a plan view of the finished can end illustrated in FIG. 33A;

FIG. 33C is a side cross section view of the finished can end illustrated in FIGS. 33A and 33B, with an inset detailed view of the portion indicated by the letter B;

FIG. 34 illustrates a first example of tooling suitable for converting the “start of a curl” shown in FIGS. 32A to 32C, to create a curl, in which the can end blank is interposed between a coin punch and a coin die which are suitably shaped to coin the final shape and dimensions of the curl;

FIG. 35 illustrates a second example of tooling suitable for converting the “start of a curl” shown in FIGS. 32A to 32C, to create a curl, in which the “start of a curl” is supported in a coin die, which is suitably shaped to control the dimensions of the curl formed around the periphery of the hole, when the coin punch is brought into contact with the coin die;

FIG. 36A illustrates a third example of tooling suitable for converting the “start of a curl” shown in FIGS. 32A to 32C, to create a curl, in a start position, in which the coin punch and coin die are spaced apart. This tooling is an enhancement of the tooling illustrated in FIG. 35, in which the can end blank is placed in the coin die and a clamp is applied around the edge of the hole; and

FIG. 36B illustrates the tooling shown in FIG. 36A in a finish position, in which the coin punch has been brought into contact with the coin die, forming a curl of controlled dimensions around the periphery of the hole.

DETAILED DESCRIPTION

Benefits of a recloseable beverage can end may include the ability to store a portion of the beverage for later use, security, cleanliness, and maintenance of the carbonation level of the beverage even if the beverage is intended to be consumed in one sitting. This may require confidence of the user that the beverage can has been properly re-closed, to maintain the carbonation level of the beverage, and to provide security against spills if the re-closed beverage can is placed in a bag, for example. However, ease of opening of the beverage can, if the beverage is intended to be consumed in one sitting, should be retained.

Accordingly, a resealable can end/beverage can is provided that provides one or more of the above identified advantages. In one embodiment, such a can end combination may include a metal can end and a resealable closure coupled to the can end. The can end may include a peripheral wall and a center panel, and the center panel may include an upper surface, an opposing lower surface, and an aperture formed there through. The closure may include a base plate and a top plate coupled to the base plate at a first location. The closure may have (i) a sealed position in which at least one of the base plate and top plate contact the center panel about the aperture to form a seal, (ii) an intermediate position in which the closure is proximate the aperture but not sealed, and (iii) a fully open position in which the aperture is exposed to enable pouring liquid through the aperture. The base plate may be downwardly moveable relative to the top plate when moved from the sealed position to the intermediate position. The base plate and top plate may translate together relative to the can end from the intermediate position to the fully open position and may also translate together relative to the can end from the fully open position to the intermediate position. The base plate may be upwardly moveable into engagement with the center panel from the intermediate position into a resealed position forming at least one of a bore seal and a flange seal.

The present invention provides a recloseable end for a beverage can and related methods for making and using the recloseable end. The embodiments described below illustrate several aspects of the present inventions and are not intended to be limiting.

Referring to FIGS. 1A-1C, a re-closable beverage can 1 includes a conventional, hollow body 5 and a recloseable end 10. The recloseable end 10 includes a metal can end 13 having a peripheral wall 12, a countersink 14 at the base of peripheral wall 12, a center panel 16. The recloseable end 10 also includes a closure 30. The present invention encompasses both unseamed can ends and can ends seamed onto a beverage can body. Accordingly, recloseable end 10 is shown, for example in FIG. 2A, formed into the shape of a double seam 18, which double seam may be conventional. Preferably, recloseable end 10 is made of conventional end stock material of conventional thickness.

As shown in FIG. 1C, the metal can end 13 of recloseable end 10 also includes an aperture 20 formed in center panel 16. The edge that forms aperture 20 preferably is formed into a curl 22. Aperture 20 is shown in the figures as circular and located in the center panel 16 in approximately the same location as opening in a conventional beverage can end. The present invention, however, is not limited to such configuration.

First embodiment closure 30, as shown for example in FIG. 2A, includes a base plate 32 and a top plate assembly 34. As explained more fully below, closure 30 is mounted onto recloseable end 10 such that closure 30 forms a bore seal 36 and a face seal 38 with the curl 22 around the periphery of the aperture.

Top plate assembly 34 includes an anchor plate 40 that is located between a cover plate 42 and a tab plate 44. A hinge 46 connects anchor plate 40 to cover plate 42. Preferably, top plate assembly 34 is formed of a commercially available thermoplastic that can be injection molded in a unitary piece, as understood by persons familiar with packaging technology.

Anchor plate 40 includes a structural portion or deck 48, which preferably is planar or nearly planar, and a skirt 50 that extends downwardly (as best shown in FIGS. 3A and 5A) from the periphery of the sides of deck 48, 48′. A stake or rivet aperture 52 is formed in deck 48, 48′. Deck 48, 48′ also includes a groove or seat 54 a extending around the circumference of aperture 52 on its topside (for example see FIG. 3A) and a ring 54 b extending around the circumference of aperture 52 on its underside (for example see FIG. 3B). A pair of post apertures 56 a and 56 b are formed in deck 48 and located on opposing sides of stake aperture 52. Preferably post apertures 56 a and 56 b extend through deck 48. An opening or slot 58 is formed in deck 48 near an end thereof

Referring to FIGS. 3A, 3B, 5A, and 5B, which show different embodiments of top plate assembly 34, cover plate 42 includes a structural portion or dome plate 62, which preferably is semi-circular and includes a skirt 64 about its periphery on its opposing sides. Skirt 64 has a cutout to accommodate hinge 46 that connects cover plate 42 to anchor plate 40. An elongated tab 66, which preferably has barbs for insertion into and retention by slot 58, extends from the underside of dome plate 62 near an edge opposite of hinge 46. Optionally, a double ended arrow indicator (shown in FIGS. 3B and 5B) may be formed on the topside of dome plate 62 to indicate an aspect of the function or step for operating closure 30, such as that required for venting, for example.

Tab plate 44 includes a structural portion or dome plate 72 (see FIG. 3A), which preferably is semi-circular and includes a skirt 74 about its periphery. An arcuate extension 76 extends outwardly from a distal end of dome plate 72 and skirt 74, and a tab 77 is formed in arcuate extension 76. Tab 77 may be rigid relative to tab plate 44, as shown in FIGS. 3A-3B. Alternatively, a tab 77′, as shown in FIG. 4B, may be formed in arcuate extension 76 and hinged to dome plate 72 or skirt 74. Tab 77′ is separated from the fixed portion of arcuate extension 76 by lateral slits or frangible connections 79.

Referring to FIGS. 3B, 4B and 5B, tab plate 44 includes a weakening or hinge 80 formed therein, preferably near anchor plate 40 and near the geometric centerline of closure 30. A shoulder, which in the first embodiment is formed by one of the walls forming hinge 80, is located between dome plates 62 and 72 of the tab plate 44 and anchor plate 40. In its as-molded, pre-installed position, and in its initial, installed state (that is, before initial opening of closure 30), weakening or hinge 80 preferably is not visible when closure 30 is viewed from above, and weakening or hinge 80 acts as a living hinge upon actuation of closure 30, as explained more fully below. As best shown in FIGS. 2A-2B, base plate 32 includes a planar (or nearly planar) plate member 82, a continuous, circumferential flange 84 extending from a periphery of plate member 82, and a continuous ring 86 extending upwardly from flange 84. Base plate 32, flange 84, and ring 86 preferably have approximately the same shape as aperture 20. Accordingly, in the embodiment shown, base plate 32, flange 84, and ring 86 are circular to match the shape of aperture 20.

Ring 86, as illustrated in FIG. 2B, includes a bead 88 extending around the outboard side thereof and a recess 90 formed below bead 88. Referring now to FIG. 6, a rivet 92, shown in its as-molded, pre-deformed state in FIG. 10, extends upwardly from plate member 82. An annular recess 94 is formed in plate member 82 around rivet 92. A pair of posts 96 a and 96 b extend upwardly from plate member 82. A pair of wings 98 a and 98 b extend on opposite sides of flange 84. One or more pimples or rounded protrusions 81 extend upwardly from the surface of plate member 82, as shown in FIG. 6.

Referring to FIGS. 2A-2C to illustrate closure 30 in its assembled state, the upper edge of double seam 18 preferably is above the highest part of closure 30. Accordingly, handling and seaming a recloseable end 10 may be accomplished with conventional equipment and technology. The end, except for the aperture 20 and closure 30, may be conventional, such as a standard B-64 end or a SuperEnd™ supplied by Crown Cork & Seal Company, Inc. U.S. Pat. No. 6,065,634 describes aspects of the latter end. The present invention also encompasses ends having other configurations; for example and not intending to be limiting, an end having a deeper center panel, a deeper countersink, and/or increased metal thickness compared with a commercial end may be employed according the desired characteristics of the end structure, materials, and function, as will be understood by persons familiar with can end technology.

In its assembled state, base plate 32 is located on the underside of center panel 16 such that the flat surface of flange 84 is in contact with the underside of curl 22 to form face seal 38, and the outboard portion of ring 86 (preferably recess 90) contacts the radially innermost portion of curl 22 to form bore seal 36. In this regard, the outer diameter of flange 84 preferably is larger than the inner diameter of curl 22 to enable engagement there between and to retain closure 30 onto center panel 16 even in conditions of high pressure within the can. For example, the beverage may encounter high temperature, rough handling, or dropping that create a high continuous or transient pressure and result in a large continuous or transient force on closure 30. The location of circumferential flange 84 beneath center panel 16 prevents or decreases the likelihood of the sudden failure (sometimes referred to as “missiling”) of the closure upon a high internal pressure condition of this type.

At conventional low pressure conditions, the bore seal 36 is the primary sealing mechanism. For example, for the embodiment shown in FIG. 2A, it is believed that the bore seal 36 is more effective than the face seal 38 below about internal pressures at about 20 psi. At about 20 psi to about 50 psi, the bore seal 36 gradually loses effectiveness because of the elongation or growth of the pour opening as the center panel deflects upwardly into a dome shape. As the bore seal 36 loses, effectiveness, however, the face seal 38 is urged against the underside of center panel 16 with increasing force by the internal pressure, which enhances the effectiveness of the face seal.

Accordingly, it is preferred that closure 30 has both a face seal 38 and a bore seal 36, which work together to seal aperture 20 even when encountering the doming deflection of center panel 16 at expected pressures. Upon venting, the release of internal pressure decreases or eliminates the doming deflection. After resealing, the center panel may again undergo doming due to increased internal pressure caused by the release of dissolved gases from liquid into the headspace, and the bore seal 36 and face seal 38 cooperation is again beneficial.

Ring 86 is sized to be insertable into aperture 20 and is resilient or flexible such that the outer diameter of bead 88 is larger than the diameter of aperture 20. Accordingly, ring 86 preferably undergoes some deflection to move from its initial, as-molded state to its installed state. Further, the installed diameter of ring 86 preferably is smaller than its initial, as-molded diameter (that is, ring 86 preferably engages curl 22 in a snap fit) to enhance the effectiveness of bore seal 36.

Rivet 92 is inserted into stake aperture 52 and in its deformed state is indicated by reference numeral 92′ in FIG. 2C. Rivet 92 is deformed to include a head 93 that affixes base plate 32 to anchor plate 40. Deforming rivet 92 to create head 93 may be accomplished by any mechanism and equipment, as will be understood by persons familiar with plastic packaging technology.

To form top plate assembly 34, cover plate 42 is pivoted from its as-molded or pre-installed position, as shown in FIGS. 3A, 3B, 4A, and 4B, relative to anchor plate 40 about hinge 46 such that cover plate 42 is located over anchor plate 40 as shown in FIG. 2B. In its installed position, dome plate 72 of tab plate 44 and dome plate 62 of cover plate 42 are oriented to align such that a peripheral edge 68 of cover plate 42 is near or abuts the shoulder or adjacent edge of dome plate 72.

Rivet 92 extends through rivet aperture 52 and head 93 is deformed to engage seat 54 a. Ring 54 b on the underside of anchor plate 40 is inserted into annular recess 94 in the base plate, which provides an interlocking engagement between base plate 32 and anchor plate 40 and top plate assembly 34. Posts 96 a and 96 b of base plate 32 are inserted into corresponding post apertures 56 a and 56 b of anchor plate 40.

Preferably, skirt 64 of cover plate 42 has a contact surface that contacts the upper of the center panel 16 to support cover plate 42. The configuration of the cover plate 42 and its thickness preferably are chosen to resist deflection, and therefore not transmit force or impact to base plate 32, but rather transmit the force or impact to center panel 16. Thus, cover plate 42 prevents or inhibits accidental opening if a downward force or impact is applied to cover plate 42. In this regard, cover plate 42 preferably is relatively rigid compared with anchor plate 40 such that anchor plate 40 enables base plate 32 to deflect downwardly relative at its periphery during the opening process.

FIGS. 5A, 5B and 7 illustrate an alternative configuration of the top plate assembly and base plate assembly, which are referred to by reference numerals 32′ and 34′ to distinguish them from the structure shown in FIGS. 3A-4B and 6. Components of the alternative configuration that are the same as those shown in FIGS. 3A and 3B and 5A and 5B are identified by common reference numerals; structure that is different in the alternative configuration from that in the first configuration uses the same reference numeral but is appended with a prime (') to indicate its alternative structure.

Closure 30′ includes a base plate 32′ and a top plate assembly 34′. Top plate assembly 34′ includes an anchor plate 40′, a cover plate 42, and a tab plate 44. Cover plate 42 and tab plate 44 may be the same as that described above with respect to FIGS. 3A-3B.

Anchor plate 40′ includes a structural portion or deck 48′ which preferably is planar or nearly planar, and a skirt 50 that extends downwardly (as oriented in FIG. 5A) from the periphery of the sides of deck 48′. A groove or seat 54 a extends around the aperture on its topside and a ring 54 b extends around the aperture on its underside. A pair of posts 96 a′ and 96 b′ are located on opposing sides of stake aperture 52 on an underside of deck 48′. An opening or slot 58 is formed in deck 48′ near an end thereof

Base plate 32′ includes a planar plate member 82′, a flange 84 extending from a periphery of plate member 82′, and a ring 86 extending upwardly from flange 84. Ring 86 includes a bead 88 extending around the outboard side thereof and a recess 90 formed below bead 88, as described above. A rivet 92, shown in its pre-deformed state in FIG. 6, extends upwardly from plate member 82′. Annular recess 94 is formed in plate member 82 around rivet 92. A pair of wings 98 a and 98 b extend on opposite sides of flange 84. A pair of recess 95 a and 95 b are located on opposing sides of rivet 92 on the topside of plate member 82′. Recesses 95 a and 95 b may be cup-like or may be through holes.

FIG. 2C is a cross sectional view through closure 30′ through rivet 92 and posts 96 a′ and 96 b′ to illustrate the functional relationship of top plate assembly 34′ and base plate 32′. In the structure shown in FIGS. 3A-7, posts 96 a and 96 b are slideably located in post apertures 56 a and 56 b.

FIGS. 1A and 2A illustrate first embodiment closure 30 in its installed state before actuation. To operate closure 30, a user places his finger under tab 77 (or tab 77′) and lifts up tab plate 44. This lifting action causes tab plate 44 to rotate about weakening or hinge 80. Accordingly, the weakening or hinge 80 forms and functions as a living hinge. Tab plate 44 preferably is pivoted about the living hinge until it is vertical, thereby enabling tab plate 44 to act as a handle or grip.

The first actuation of the living hinge preferably creates stress whitening at or around weakening or hinge 80. The thermoplastic material of top plate assembly 34 may be chosen to ensure that stress whitening is visible and may be chosen to enhance the stress whitening effect. Preferably top plate assembly 34 has a color other than white to enhance the visibility of the stress whitening. Accordingly, the stress whitening of the living hinge provides evidence that closure 30 is not in its as-installed state and had been previously opened. Also, tab plate 44 preferably does not fully reseat to its original, initial position after the first time it is pivoted upward, and in this way provides tamper evidence. The broken condition of the frangible connections 79 of tab 77′ may also provide tamper evidence.

The arrows on the topside of cover plate 42 indicate that upright tab plate 44 may be rotated or twisted in either direction, like the action of turning a dial. Posts 96 a and 96 b (or 96 a′ and 96 b′) transmit torque between top plate assembly 34 (or 34′) and base plate 32 (32′). The rotation of tab plate 44 causes the entire closure 30 to rotate, which moves one of wings 98 a and 98 b against the underside 15 of end countersink 14.

As wing 98 a or 98 b is forced beneath countersink underside 15 by the rotation, base plate 32 flexes or tilts to break the bore seal 36 and face seal 38. In this regard, a portion of base plate 32 is displaced relative to center panel 16 such that a portion of ring 86 becomes disengaged from curl 22 as bead 88 is pulled below curl 22 over a portion of its circumference. Breaking the seal in this way enables venting of the pressure in the headspace beneath recloseable end 10. The vented position, which is intermediate between the fully closed and fully open positions, is shown in FIGS. 1B and 2D.

From the vented position, the user continues to grip tab plate 44 and pulls or slides closure 30 to expose an end of the aperture 20 to enable drinking or pouring from the can end. Thus, closure 30 may be actuated by gripping tab plate 44, twisting it, and pulling it, without the user letting go of tab plate 44.

To the extent necessary, the attachment of top plate assembly 34 to base plate 32 by rivet 92 has the inherent capability of flexing to enable base plate 32 to ride underneath center panel 16 and to enable tab plate 44 to ride overtop center panel 16. Posts 96 a and 96 b (or 96 a′ and 96 b′) are longitudinally slideable in corresponding post apertures 56 a and 56 b (or recesses 95 a and 95 b) to enhance the ability of base plate 32 to flex or deform relative to top plate assembly 34 while transmitting torque from top plate assembly 34 to base plate 32. The fully open and operational position of closure 30 is shown in FIGS. 1C and 2E.

In the fully open position, protrusions 81 (not shown in FIGS. 1C and 2E but shown in FIG. 6) are located and sized to contact the underside of center panel 16 or, preferably, to contact curl 22. Protrusions 81 act as spacers to increase the angle at which base plate 32 is oriented, and therefore increase the area at which the air can rush into can headspace during pouring. This increased vent area for inrushing air diminishes the glugging effect and increases the flow rate during pouring.

FIGS. 8A-8C illustrate an embodiment of the resealable can end by which venting of the closure may be further enhanced. Base plate 32, as shown in FIG. 6 may be provided with a vent groove 33, which directs the inrushing air into the headspace of the beverage can 1 (see FIG. 1C). Additionally, closure 30 a (see FIGS. 10A-10B) is provided with vent slots 41 (see FIG. 8B), which together with vent arches 63 define a flow path for the inrushing air from the ambient conditions outside the beverage can 1 to the headspace inside the beverage can.

Referring to FIGS. 9A-9B, to reclose closure 30, a user grasps tab 77 and pushes or slides closure 30 over aperture 20 until ring 86 aligns with aperture 20. The user then pulls generally upwardly on tab 77 and tab plate 44 with a force sufficient to deflect ring 86 such that bead 88 snaps over curl 22.

In this way, the peripheral rim of curl 22 engages ring surface or recess 90 and the lower portion of curl 22 engages the upper face of base plate flange 84, thereby recreating bore seal 36 and face seal 38 and resealing the closure. As dissolved gases in the beverage move from the liquid into the headspace beneath recloseable end 10, the pressure in the headspace increases above atmospheric pressure. The resultant force on base plate 32 creates an upward force on flange 84, which enhances face seal 38.

Referring to FIG. 9B, as the user continues to lift tab 77, deflecting tab plate 44 the hinge 80 is opened to its full extent and further lifting of tab plate 44, causes the plate member 82 to cover and seal the aperture 20 as previously described.

For embodiments in which the ring has a bead 88, the action of bead 88 moving over curl 22 may create an audible click, which provides an indication to a user that the closure has been reclosed and resealed. The length, thickness, shape, and material properties may be chosen to enhance this audible click. The inventors notice that the click is louder than expected, and surmise that the center panel acts as a portion of a sound box to amplify the click.

FIGS. 10A-12B illustrate variations of the top plates of resealable closures. Closures 30 a, 30 b, and 30 c illustrate configurations of the center panels and upper portions of the closure to provide, among other things, visual cues to a user during the reclosing process as to the proper position of the closure.

FIGS. 10A-10B illustrate a closure 30 a having a cover plate 42 a and tab plate 44 a that pivots about hinge 80 a. Tab plate 44 a includes concave recesses 45 a. Optionally, the center panel may include recesses (not shown in the figures) into which the underside of concave recesses 45 a fit into. The center panel 16 a includes a recess 97 a to ease access to the distal end of tab plate 44 a by a user's finger and embosses 99 a that can be aligned with a waist portion of the closure 30 a. In this regard, embosses 99 a provide a visual indication to a user that closure 30 a is in proper position for reclosing when embosses 99 a are aligned with the waist or other visual indicator of closure 30 a.

FIGS. 11A-11B illustrate closure 30 b of having a cover plate 42 b and tab plate 44 b that pivots about hinge 80 b. Center panel 16 b includes a recess 97 b to enhance finger access. The location of panel aperture (not shown in FIGS. 11A-11B) and configuration of cover plate 42 b is chosen such that in its closed position, an arcuate perimeter of closure 30 b is aligned with the panel reinforcing bead, which provides a visual indication to a user that closure 30 b is in proper position during the reclosing process.

FIGS. 12A-12B illustrate closure 30 c having a cover plate 42 c and tab plate 44 c that pivots about hinge 80 c. Center panel 16 c includes a recess 97 c to enhance finger access. Recess 97 c is curved at approximately the same curvature as the distal edge of tab plate 44 c. A pair of straight embosses 99 c are formed on opposing sides of closure 30 c in center panel 16 c. Embosses 99 c are angled to match the angle formed by opposing edges of closure 30 c. In this regard, the corresponding curvatures of recess 97 c and the distal edge of tab plate 44 c and the embosses that bracket closure 30 c provide a visual indicator to a user during the reclosing process that closure 30 c is in proper position.

The operation of closures 30 a, 30 b, and 30 c is described, for simplicity, with respect to the reference numerals for closure 30 a. It is understood that the description also applies to the operation of closures 30 b and 30 c. The configuration of hinge 80 a limits the magnitude of pivoting of tab plate 44 a to 90 degrees such that tab plate 44 a cannot pivot significantly past the upright position. To accomplish this limit, the hinge preferably is formed near the bottommost surface of tab plate 44 a.

While tab plate 44 a is in its fully upright position, its wing-nut-like shape, in which its opposing ears protrude above its lower center, provides a cue for turning. Further, to actuate tab plate 44 a from its fully open position to the closed position, a user may merely pull or push tab plate 44 a toward the close position. Upon proper alignment, the torque created by the user force applied near the top of tab plate 44 a may pull the base plate up to engage the bore seal.

FIGS. 13A-13D show view of an alternative tamper evidence (TE) structure, which may incorporated into the closure either to replace or in addition to the stress whitening previously described. This TE structure comprises at least one TE rivet 100, which is accommodated in one or more associated holes 47 on the tab plate 44. The advantage of this TE over previous proposals is that it is impossible to lift the tab plate 44 to achieve venting or to slide the closure open, without breaking the TE structure.

The TE arrangement is also advantageous, because the tab plate 44 is held down on the closure, even when the beverage can 1 is pressurized and thus there is less risk of “tab over chime”. This alternative TE rivet 100 is visibly evident to the user and may be enhanced by the use of different colors for the TE rivet 100 and the tab plate 44. The TE bridges between the TE rivet 100 and the one or more associated holes 47 in the tab plate 44 may be arranged so that they break successively, to minimize the opening force. Furthermore, the TE bridges may be tapered so that they remain on the TE rivet 100 rather than in the one or more associated holes 47 on the tab plate 44.

The TE rivet 100 is recessed into the tab plate 44 and the one or more associated holes 47 is small enough to prevent finger access for accidental opening of the tab plate 44. The TE rivet 100 is recessed into the tab plate 44 so that when the closure slides open it does not catch the double seam 18. The top of the TE rivet 100 acts to tilt the plate member 82 and provide an air vent path into the headspace during dispensing of the product.

FIGS. 14A-21B illustrate another embodiment of a resealable and recloseable end 110, which includes a peripheral wall 112, a countersink 114 at the base of peripheral wall 112, a center panel 116, and a closure 130. Recloseable end 110 has an aperture 120 formed in center panel 116 about a curl 122, which may prevent a user from being cut by a sharp, raw edge. Curl 122 also interacts with closure 130 to form a seal, when closure 130 is in its closed position.

Closure 130 includes a base plate 132 and a top plate assembly 134, and forms a bore seal 136 and a face seal 138 with curl 122. Top plate assembly 134 includes a tongue plate 140, a cover plate 142, and a tab plate 144. In its assembled state, tongue plate 140, is located below cover plate 142 and above and base plate 132. A hinge 146 connects tongue plate 140 to cover plate 142.

Tongue plate 140 includes an aperture 149, which in the embodiment shown in FIG. 14A is a slot. Tongue plate 140 extends from hinge 146 and includes a spring 150 from which a plug 152 downwardly extends. Plug 152 includes a longitudinal slot-like opening that forms a pair of opposing windows 156. The pair of opposing windows 156 open at the upper end of plug 152. A continuous circular sealing portion 157 is below the pair of opposing windows 156. When the plug 152 is in its closed position, the sealing portion 157 seals a vent aperture 191. However, when the plug 152 is in its venting position, the pair of opposing windows 156 form vent pathways or a fluid connection between the headspace of the beverage can 1 and the external environment.

Cover plate 142 includes a structural portion or dome plate having a skirt and a cut-out to receive a lever arm, as explained below. One or more rivets 192 extend downwardly from the underside cover plate 142 through aperture 149.

Tab plate 144 includes a structural portion or dome plate, which preferably is arcuate and includes a skirt about its periphery. A lever arm 173 extends from dome plate into the cutout formed in dome plate. A tab 176 extends outwardly from the dome plate opposite lever arm 173. As tab 176 is lifted by a user to open the can, lever arm 173 pushes plug 152 against spring 150 and exposes the pair of opposing windows 156, which form vent pathways between the headspace of the beverage can 1 and the external environment. As tab 176 is lifted further, base plate 132 and face seal 138 are disengaged and the closure may be opened, exposing aperture 120 in the center panel 116.

Upon reclosing, a user re-engages base plate 132 and face seal 138 by manipulating tab 176 and spring 150 returns plug 152 to its sealed position.

A pair of side supports 181 extends downwardly from the underside of lever arm 173 to stiffening the lever arm. The distal end of tongue plate 140 is located between side supports 181. Tab plate 144 includes a weakening or groove 180 formed therein.

Referring to FIG. 19A, base plate 132 includes a planar (or nearly planar) plate member 182, a continuous, circumferential flange 184 extending from a periphery of plate member 182, and a continuous ring 186 extending upwardly from flange 184. Base plate 132, flange 184, and ring 186 preferably have approximately the same shape as aperture 120. Accordingly, in the embodiment shown, base plate 132, flange 184, and ring 186 are circular to match the shape of aperture 120. Base plate 132 also includes an aperture 191 that forms a sealing surface 193, as best shown in FIG. 14B, from which the majority of tongue plate 140 is removed for clarity.

In its assembled state, base plate 132 is located on the underside of center panel 116 such that the flat surface of flange 184 is in contact with the underside of curl 122 to form face seal 138, and the outboard portion of ring 186 contacts the innermost portion of curl 122 to form bore seal 136.

Plug 152 extends through aperture 191 in base plate 132 and is retained by a rivet head 154. Plug 152 may be molded in a cylindrical shape and deformed during assembly with base plate 132 or may be formed with an olive or bead (not shown in the figures) such that plug 152 is inserted through aperture 191 in a snap fit. Sealing surface 193 contacts continuous sealing surface 157 of plug 152 to seal aperture 191 while closure 130 is in its original or reclosed position. In the configuration shown in FIG. 14A, spring 150 exerts an upward force on plug 152 that tends to return the plug to its unvented state.

FIGS. 20A-20B show another embodiment of a plug 152′ that includes a sealing portion 157′ and a location portion 158′ of reduced diameter, adapted to ensure that the plug assembly remains aligned with aperture 191, but provides a vent pathway between the headspace inside the can and the external environment. Plug 52′ has a base plate 195, rivet holes 196, and a spring 197 to bias plug 152′ towards its sealed position. Base plate 195 is attached to the underside of the closure base plate by rivets that extend through rivet holes 196. Spring 197 urges plug 152′ upwardly such that a continuous sealing surface of plug 152′ engages and seals against the aperture 191. Upon lifting of tab 176 by a user, a lever arm 173 is actuated to push plug 152′ downwardly to vent and open, as will be understood based on the discussion of plugs above.

Referring to the second embodiment closure 130, to actuate closure 130 from its original, closed position to a vented, intermediate position, tab 176 is lifted upwardly to pivot tab plate 144 about the hinge formed by groove 180. The bottom surfaces of side supports 181 contact the upper surface of base plate member 182 as lever arm 173 pivots counterclockwise. Lever arm 173 contacts plug 152 and drives it downwardly until the pair of opposing windows 156 are exposed beneath center panel 116 (such as, for example, corresponding to approximately 30 degree rotation of tab 176), which enables communication between the headspace in the can and the ambient atmosphere through at least one of the pair of opposing windows 156. In this way, internal can pressure is controllably vented before fully opening closure 130. However, location portion 158′ remains aligned in the aperture 191.

After venting, a user may rotate tab 176 more fully, such as approximately to 45 degrees, and optionally apply a downward force either by directly contacting and pushing onto closure 130 or by transmitting a force through the tab 176. The action of tab 176 and the optional downward force disengages bore seal 136 and face seal 138. Rotation of tab 176 and the optional downward force may continue until base plate 132 easily clears center panel 116 to enable sliding of closure 130 to expose aperture 120. The gap between the top of ring 186 and curl 122 is approximately 0.76 mm (0.299 inch).

To reclose, a user may grasp tab 176 and pull or push closure 130 until it is aligned with aperture 120, then put upwardly to engage bore seal 136 and face seal 138.

FIGS. 22-25 illustrate another embodiment of resealable and recloseable end 210, which includes a peripheral wall 212, a countersink 214 at the base of peripheral wall 212, a center panel 216, and a closure 230. Recloseable end 210 includes an aperture 220 formed in center panel 216 about a curl 222.

Closure 230 includes a base plate 232 and a top plate assembly 234, and forms a bore seal 236 and a face seal 238 with curl 222. Top plate assembly 234 includes a cover plate 242 and a tab plate 244.

Cover plate 242 includes a pivotable structural portion or dome plate 262 and an anchor plate 263. Dome plate 262 and anchor plate 263 are separated by a hinge 280 that functions as a living hinge, and may have the stress whitening, tamper evident features described above.

Cover plate 242 includes a cylindrical pin 255 extending downwardly from its underside. Cover plate 242 is separated from tab plate 244 by a living hinge 277, which may function as a living hinge and as tamper evidence. Anchor plate 263 includes a rivet aperture 252 and an arcuate slot 253 there through.

Base plate 232 includes a planar (or nearly planar) plate member 282, a continuous, circumferential flange 284 extending from a periphery of plate member 282, and a continuous ring 286 extending upwardly from flange 284. A pair of wings 298 a and 298 b extend on opposite sides of flange 84, as shown in FIG. 25.

Base plate 232, flange 284, and ring 286 preferably have approximately the same shape as aperture 220. Base plate 232 includes a rivet 292 and a pair of arcuate tongues 293 that extend upwardly from plate member 282.

Center panel 216 also includes an aperture 350 that is spaced apart from pour aperture 220. A grommet or insert 352 is affixed into aperture 350, preferably in a press fit. Insert 352 has a through arcuate slot 253 defined by a sealing surface 254. Preferably, base plate 232 and insert 352 are injection molding in a unitary piece such that base plate 232 and insert 352 are held together by bridges. Upon application of the unitary, injection molded part to center panel 216, the bridges are ruptured, which enables base plate 232 to function as described herein.

In its assembled state, base plate 232 is located on the underside of center panel 216 such that the flat surface of flange 284 is in contact with the underside of curl 222 to form face seal 238, and the outboard portion of ring 286 (preferably recess 290) contacts the innermost portion of curl 222 to form bore seal 236.

Rivet 292 extends through rivet aperture 350 in anchor plate 263 to affix the top and bottom plates together. Arcuate tongues 293 extend into arcuate slots 253. Cylindrical pin 255 is located in insert aperture 250 such that cylindrical pin 255 forms a seal with aperture sealing surface 254.

To actuate closure 230, a user may place a finger beneath tab plate 244 to rotate dome plate 262 of cover plate 242 upwardly about hinge 280, then translate closure 230 relative to aperture 220. Wings 298 a and 298 b preferably are not employed for the opening process, but rather are used as guides during assembly and application of closure 230 to center panel 216.

From the vented position, the user continues to grip tab plate 244 and pulls or slides closure 230 to expose end aperture 220 to enable drinking or pouring from the can end. Thus, closure 230 may be actuated by gripping tab plate 244, twisting it, and pulling it, without the user letting go of tab plate 244.

To the extent necessary, the attachment of top plate assembly 234 to base plate 232 by rivet 292 has the inherent capability of flexing to enable base plate 232 to ride underneath center panel 216 and to enable tab plate 244 to ride overtop center panel 216.

To reclose closure 230, a user grasps tab plate assembly 234 and pushes or slides closure 230 over aperture 220 until ring 286 aligns with center panel aperture 220. The user then pulls generally upwardly on tab plate 244 with a force sufficient to deflect ring 286 such that bead 288 snaps over curl 222.

As described above in relation to recloseable beverage can 1, and referring now to FIGS. 26A-26D, the metal can end 13 according to the invention has an aperture 20 through which the contents of the can 1 to which the metal can end 13 is affixed, may be dispensed from the can by a user and then the can 1 may be closed and re-sealed. The aperture 20 is adapted to receive a separate closure 30 (such as those described above) which may be moved relative to the metal can end 13 between a closed position, in which the aperture 20 is closed and sealed, and an open position, in which the aperture 20 or a major portion thereof is exposed allowing the contents of the can to be dispensed. The metal can end 13 is fixed to a can body (not shown) using conventional joining techniques, such as double seaming etc.

Referring to FIG. 26D in particular, W of the metal can end 13 according to the invention is less than 4 mm, preferably less than 3 mm. (In the end described in EP 1607341 A (TOYO SEIKAN) 21 Dec. 2005 currently on sale, W is approx. 4 mm.) X is preferably less than 3 mm.

A method and apparatus for producing such a metal can end 13 is also described by way of example. This has fewer steps than described and shown in any of FIGS. 33, 34, 35 and 36 in EP 1607341 A (TOYO SEIKAN) 21 Dec. 2005.

FIGS. 27A-33A show a stepwise progression of the formation of the metal can end 13 culminating in a finished metal can end 13 and the tooling required to complete each step in the fabrication.

The first step of the method is to pierce an aperture 20 through the metal can end 13 as shown in FIGS. 28A-28C. This step may be carried out using a conventional punch and die arrangement, and the end panel may be clamped against the face of the die during piercing. The metal disc created in the piercing step may be discarded or may be saved for another purpose.

The second step of the method is to depress an annular region 8 d′ around the periphery of the aperture 20 as shown in FIGS. 29A-30C. In the tooling of FIG. 29A, the aperture 20 is positioned on a location tool 35 d before being clamped between the opposing faces of the clamp 40 d and die 30 d. The annular region 8 d′ is then depressed into the annular profile of the die 30 d by the movement of the annular punch 45 d.

Preferably, the periphery of the aperture 20 is formed into a lip 9 d by drawing it between the inner diameter of the annular punch 45 d and the inner wall of the annular profile of the die 30 d. The lip 9 d assists smooth forming of the curl in the final step.

The radius between the outer diameter and the end face of the annular punch 45 d, the radius between the outer wall of the annular profile and the adjacent face of the die 30 d, and the depth of the annular region 8 d′ approximate to the desired final dimensions of the curl. This avoids excessive working or re-working of the metal, and helps to preserve the surfaces to provide sealing in subsequent use.

Formation of the annular region 8 d′ helps to remove any slackness of the metal in the end panel, and helps to stiffen the periphery of the aperture 20.

While it is preferred to carry out the first step of piercing and the second step of forming the depression separately as described above, it is possible to combine these two steps into one, to reduce the overall number of steps required. For example this can be done by removing the location tool 35 d from the tooling of FIGS. 29A-29B, providing a cutting edge in a modified version of the die 30 d and providing a piercing punch. With such tools it is possible to sequentially clamp the end panel, then pierce a hole and then form an annular depression.

The third step of the method is to draw the inner portion of the annular region 8 d′ upwards using the tooling of FIGS. 31A-31B to form the “start of a curl” 8 d″ shown in FIGS. 32A-32C.

In the tooling of FIG. 31A, the end panel is firstly clamped between the faces of the die 60 d and clamp 70 d, and the outer portion of the annular region 8 d′ is supported by the profile of the die 60 d. The inner portion of the annular region 8 d′ is then formed into the “start of a curl” 8 d″ by movement of the punch 50 d.

The profile of the die 60 d approximates to the desired final internal dimensions of the curl. This avoids excessive working or re-working of the metal, and helps to preserve the surfaces to provide sealing in subsequent use.

While it is preferred to carry out this third step of forming the “start of a curl” 8 d″ between forming the annular depression and the final step of creating the final curl, it is possible to omit this third step. Omission of this third step is possible if the inside diameter of the lip 9 d approximates to the final inside diameter of the curl, and the height of the lip 9 d is tall enough to form into the final curl. The height of the lip 9 d may be made tall by providing the die 30 d with an inner face positioned above the outer face.

The final step of the method is to form the final shape of the curl using tooling arranged to accurately control the dimensions and condition of those surfaces against which the closure is to subsequently fit and seal.

The tooling of FIG. 34 shows a punch 80 d and a die 90 d in a closed position. The curl 8 d has been formed to a final shape and dimensions by the profiles of the punch 80 d and die 90 d.

The tooling of FIG. 35 shows an alternative punch 80 d′ and an alternative die 90 d′, in a closed position. The curl 8 d has been formed to a final shape and dimensions by the alternative profiles of the punch 80 d′ and die 90 d′.

Either the tooling of FIG. 34 or the tooling of FIG. 35 may be preferred depending upon which surfaces of the curl 8 d are to be used to fit and seal against the closure (not shown), and so are important to be supported by the tooling profiles.

The tooling of FIGS. 36A-36B shows an improved version of the tooling of FIG. 35. FIG. 36A shows the end panel clamped between a die 90 d″ and an annular clamping ring 85 d, and FIG. 36B shows the same tooling after a punch 80 d″ has been moved to form the final curl 8 d. Clamping the end panel in this way prevents the metal of the curl being pushed outwards from the profile of the die during forming, and so produces a better curl and prevents slackness being created in the metal of the panel surrounding the aperture.

The punch 80 d″ of FIGS. 36A and 36B has a downward projection at the periphery of its profile, which directs the cut-edge of the curl downwards to reduce exposure of the cut-edge.

The method described above avoids excessive working of surfaces that are required for sealing, and the progressive formation of annular features prevents the formation of radial wrinkles and the risk of radial splits in the metal. Although the method is described in detail for producing accurate, round apertures for sealing with separate round closures, it will be apparent to the person skilled in the art how this method may be adapted to produce accurate, non-round apertures if desired.

The method has been described as it relates to the formation of a curled aperture in a sheet metal end panel, which is adapted to be joined to a container body, such as a beverage can body. Of course, the metal of the end panel may be coated with polymer or other material and an advantage of the method of the invention is the preservation of such coatings. Of course it is also possible for the aperture of the invention to be formed in the opposite end panel of a sheet metal container body, such as a beverage can body.

The present invention is illustrated by the description of several embodiments and aspects. The present invention, however, is not limited to the particular embodiments described herein. Rather the present invention encompasses any combination of the features of any of the embodiments and aspects and natural variations thereof, as will be understood by persons familiar with closure technology. 

We claim:
 1. A metal can end for a beverage can body, the can end comprising: a center panel surrounded by a seaming portion adapted to be joined to the periphery of the beverage can body by a double-seam, the center panel defining an aperture through which the contents of the beverage can body may be dispensed, a peripheral edge of the aperture finished by a curl and the aperture adapted to receive a separate closure capable of sliding relative to the center panel between a closed position, in which the aperture and the closure together form a seal, and an open position, in which the aperture is exposed.
 2. A metal can end according to claim 1, wherein the aperture curl stiffens the center panel and enhances the seal between the aperture and the separate closure, when the separate closure is in its closed position.
 3. A metal can end according to claim 1, wherein the closure is made of a plastics material.
 4. A metal can end according to claim 1, wherein the center panel defines an exterior surface that receives the separate closure, and an edge of the curl abuts the exterior surface of the center panel.
 5. A metal can end for a beverage can body, the can end comprising: a peripheral wall; a countersink; and a center panel, the center panel defining an aperture through which the contents of the beverage can body may be dispensed, the center panel including a curl disposed about the aperture, the center panel adapted to receive a separate closure configured to slide along the center panel between: i) a sealed position, in which the closure contacts the center panel about the aperture to form a seal, ii) an intermediate position, in which the closure is proximate the aperture but not sealed, and (iii) a fully open position, in which the aperture is exposed to enable pouring the contents of the beverage can body through the aperture.
 6. A metal can end according to claim 5, wherein the curl stiffens the center panel and enhances the seal between the aperture and the separate closure, when the separate closure is in its sealed position.
 7. A metal can end according to claim 5, wherein the closure is made of a plastics material.
 8. A metal can end according to claim 5, wherein the center panel defines an exterior surface that receives the separate closure, and an edge of the curl abuts the exterior surface of the center panel.
 9. A metal can end according to claim 5, wherein the distance between an edge of the center panel and the aperture is less than 4 mm.
 10. A metal can end according to claim 9, wherein the distance between the edge of the center panel and the aperture is less than 3 mm.
 11. A metal can end according to claim 5, wherein the can end is produced from polymer-coated metal.
 12. A method of manufacturing a metal can end for a beverage can body, the method comprising the steps of: pressing a metal can end from sheet metal, the metal can end having a center panel surrounded by a seaming portion, the seaming portion being adapted to be joined to a periphery of the beverage can body by a double-seam; cutting an aperture through the center panel of the metal can end; forming a depression around the aperture, at least part of which is formed to create a preliminary curl around the aperture; and coining the preliminary curl to form a curl around the aperture.
 13. A method of manufacturing a metal can end according to claim 12, wherein the interaction between a coining die and a coining punch controls the dimensions of the aperture curl and thereby the diameter of the aperture.
 14. A method of manufacturing a metal can end according to claim 12, further including controlling the dimensions of the curl and thereby the diameter of the aperture using a coining die.
 15. A method of manufacturing a metal can end according to claim 12, further including determining the diameter of the aperture using a single tool piece.
 16. A method of manufacturing a metal can end according to claim 13, further including clamping the metal can end around the aperture.
 17. A method of manufacturing a metal can end according to claim 12, further including controlling the curl dimensions required for sealing. 